In data center environments, rack units may house many server devices. Each server device may be configured to host one or more physical or virtual host devices. The servers in the rack units are connected to Top of Rack (ToR) switch devices. The ToR switches, in turn, are connected to other ToR switches via a spine switch or spine fabric. Data communications may be exchanged between host devices (physical and/or virtual) in different rack units. For example, packets of data communications may be sent from a virtual host device in one rack unit to a virtual host device in another rack unit. These packets may be routed between corresponding ToR switch devices and the spine switch. The ToR switches are configured to store address information associated with the host devices in the data center environment.